M. R. Infante

Lipopeptidic surfactants: I. Neutral N-lauroyl-I-arginine dipeptides from pure amino acids

Neutral Nα-lauroyl-dipeptides such as Nα-lauroyl arginylglycine and Nα-lauroyl-arginylphenylalanine as methyl ester (cationic surfactants) and free acid (amphoteric surfactants) derivatives have been prepared by synthetic methods. Fundamental surfactant properties and antimicrobial activity have been evaluated.The properties of these compounds have been compared to the properties of the monomer derivatives Nα-lauroyl-arginine methyl ester (cationic) and Nα-lauroyl-arginine (amphoteric). These new molecules are very soluble in water, good surfactants, and exhibit a good antimicrobial activity, independently of their ionic character.

Lipopeptidic surfactants. II. Acidic and basic Nα-lauroyl-L-arginine dipeptides from pure amino acids

In this paper, the second part of a systematic study whose aim deals with the influence of the terminal amino acid side chain on the properties of Nα-lauroyl arginyl dipeptides is reported. Nα-lauroyl arginyl dipeptides that contain an acidic amino acid (glutamic acid) or a basic amino acid (lysine) as terminal amino acid have been prepared by peptide synthesis methods. These compounds have been synthesized as methyl esters (cationic surfactants) and free α-carboxylic acids (amphoteric surfactants), and their fundamental surfactant properties and antimicrobial activity have been evaluated. The properties of these compounds have been compared to the properties of the cationic monomer derivative methyl ester of Nα-lauroyl arginine and of the amphoteric monomer derivative Nα-lauroyl arginine reported earlier.The compounds are soluble in water and show surface activity, although in the case of the amphoteric Nα-lauroyl arginyl dipeptide containing glutamic acid these two properties depend on the solution pH. The cationic Nα-lauroyl arginyl dipeptides are antimicrobial agents. However, only the amphoteric compound containing lysine may be considered antimicrobial.

Wool Treatments with Mixtures of Sulphite and Amphiphilic Cationic Protein Hydrolysate

Derivatives of collagen and keratin hydrolysates are frequently used to improve the cuticular surface of human hair, mainly when an oxidative or reductive treatment is involved. In this paper, a similar reductive treatment applied to wool in the presence of an amphiphilic cationic protein hydrolysate leading to a considerable reduction in shrinkage with no significant change in physico-chemical properties, is reported. The influence of the experimental treatment conditions on the effectiveness of the process by evaluation of different parameters such as shrink-resistance, wetting time, cysteine formation, subjective handle assessment, mechanical properties and dyeing behaviour at low temperatures is studied and discussed.

Synthesis and properties of Nα-lauroyl-L-arginine dipeptides from collagen-lauroyl-L-arginine dipeptides from collagen

In order to obtain protein-based amphoteric surfactants with antimicrobial properties, Nα-lauroyl arginine dipeptides have been prepared by condensation between Nα-lauroyl arginine and amino acids which come from a collagen hydrolysate. Some surfactant properties and the minimum inhibitory concentration against Gram positive and Gram negative bacteria have been evaluated. All types of compounds presented a surfactant-like behavior. Furthermore, the compounds described in this paper may be considered as mild preservative or protective substances.

THE INTERACTION OF IONIC SURFACTANTS-RESINS FOR IMPROVING EXHAUSTION ADHESION AND SPREADING OF PREPOLYMERS ON KERATIN FIBRES

ABSTRACT A study of the effect of the aggregates formed between Hercosett and alkylsulphates (C8-C14) in preventing the shrinkage of wool samples pretreated with hydrogen peroxide is reported and a kinetic study of the formation of these aggregates as well as a mechanism by which they exhaust on wool fibres are suggested.